SnodFish is an open source API back-end server. Rather than run something like haproxy in front of nginx, and then your choice of front-end (such as sinatra for Ruby heads), SnodFish listens on a well-known port, accepts REST commands over an HTTP interface, and translates them into JSON RPC calls to one or more back-end servers.
You create a mapping by defining how you want the GET, PUT, POST and DELETE urls to be handled, and the URL as well as any passed-in JSON is executed by one or more back-ends via one or more RPC mechanisms.
For now, the only supported RPC is ZeroMQ.